1. Technical Field of the Invention
The present invention relates to integrated telecommunication systems and, more particularly, to a system and method for supporting multiple endpoints in a single device disposed in a packet-switched network such as, for example, a network using the Internet Protocol (IP).
2. Description of Related Art
Coupled with the phenomenal growth in popularity of the Internet, there has been a tremendous interest in using packet-switched network infrastructures (e.g., those based on IP addressing) as a replacement for the existing circuit-switched network infrastructures used in today""s telephony. From the network operators"" perspective, the inherent traffic aggregation in packet-switched infrastructures allows for a reduction in the cost of transmission and the infrastructure cost per end-user. Ultimately, such cost reductions enable the network operators to pass on the concomitant cost savings to the end-users.
Some of the market drivers that impel the existing Voice-over-IP (VoIP) technology are: improvements in the quality of IP telephony; the Internet phenomenon; emergence of standards; cost-effective price-points for advanced services via media-rich call management, et cetera. One of the emerging standards in this area is the well-known H.323 protocol, developed by the International Telecommunications Union (ITU) for multimedia conferencing over packet-based networks. Using the H.323 standard, devices such as personal computers can inter-operate seamlessly in a vast inter-network, sharing a mixture of audio, video, and data across all forms of packet-based and circuit-switched network portions.
The H.323 standard defines four major types of components for forming an inter-operable network: terminals, gateways, gatekeepers and multipoint control units (MCUs). In general, terminals, gateways and MCUs of an H.323-based network are referred to as xe2x80x9cendpoints.xe2x80x9d Gateways are typically provided between networks (or network portions) that operate based on different standards or protocols. For example, one or more gateways may be provided between a packet-switched network portion and a circuit-switched network portion. Terminals are employed by end-users for accessing the network or portions thereof, for example, for placing or receiving a call, or for accessing multimedia content at a remote site.
The gatekeeper is typically defined as the entity on the network that provides address translation and controls access to the network for other H.323 components. Usually, a gatekeeper is provided with the address translation capability for a specified portion of the network called a xe2x80x9czone.xe2x80x9d Accordingly, a plurality of gatekeepers may be provided for carrying out address translation that is necessary for the entire network, each gatekeeper being responsible for a particular zone. In addition, gatekeepers may also provide other services to the terminals, gateways, and MCUs such as bandwidth management and gateway location.
The H.323 standard defines two types of addresses associated with each endpoint: a transport address (which, for example, corresponds to the IP address and the port address of a terminal operated by the end-user) and an alias address. An endpoint may have one or more aliases associated with it. Exemplary aliases may include the well-known E.164 telephone numbers, H.323 IDs (such as names, email-like addresses, etc.), and so on. The address translation service of the gatekeeper provides an alternative method of addressing an endpoint wherein a user-friendly alias (e.g., the E.164 telephone number) associated therewith may be translated into its appropriate transport address used by the protocol.
It can be readily appreciated that providing multiple endpoints, each having its own unique alias, within a single device (e.g., an information appliance (IA)) with one transport address is a very advantageous feature. For example, a single IA may be provided with a facsimile transmission function, a home telephone function, and a business telephone function, each operating as a separate endpoint having its own unique E.164 alias address. The IA itself is provided with a single transport address for facilitating the address translation associated with the endpoints. Accordingly, by concentrating multiple endpoints in a single transport address for a device, it is feasible to conserve the transport-related address space of the gatekeeper and help reduce the depletion of resources associated therewith.
Providing multiple endpoints in a single device is also useful in a VoIP telecommunications network wherein appropriate cellular telephone infrastructures are integrated within an H.323-based network via one or more gateways. For example, it is typically required that multiple mobile stations (MSs) be accessible at any time via a gateway in a VoIP network wherein each of the MSs are usually known only by their E.164 aliases. Again, the gateway is provided with a single, unique transport address for facilitating suitable address translation.
Current solutions for providing multiple endpoints in a single device have various drawbacks and shortcomings. For example, to allow multiple endpoints, the H.323 standard permits the use of dynamic values instead of a fixed value for the call signaling port. This feature has the disadvantage of allowing the access for one endpoint at a time. Moreover, it prevents interoperation with endpoints outside the zone of the governing gatekeeper except via a gateway in the zone.
Also, in the existing multiple endpoint solutions, when multiple aliases are mapped to a single transport address, all alias addresses associated with the transport address need to be registered at the gatekeeper at the same time. Consequently, if one of the plural endpoints needs to be replaced or changed for some reason, all the remaining endpoints are required to register again at the gatekeeper. In other words, the multiple endpoints cannot be registered separately or individually. For example, if five alias addresses are mapped to a single transport address, and one alias address is to be replaced or deleted, all five including the replacement alias or the other four (if one is merely deleted) aliases need to be re-registered at the gatekeeper. Those of ordinary skill in the art can readily appreciate that such a condition leads to unacceptable situations in VoIP cellular telephone systems where multiple MSs may have to be registered at the gatekeeper via a gateway at such different times as required by the end-users.
Based on the foregoing, it is apparent that in order to address these and other problems of the current solutions set forth above, what is needed is a system where multiple endpoints are provided within a single device such that individual registration/deregistration of the associated aliases is feasible. The present invention provides such a solution.
The present invention is directed to a method of registering multiple endpoints at a gatekeeper disposed in a packet-switched network. Preferably, the multiple endpoints, each having a separate alias address, are provided within a proxy device. The method then configures the proxy device by setting its alias and transport addresses. The proxy device is then registered at a registry associated with the gatekeeper, whereby the transport address and the alias address of the proxy device are matched. Each endpoint that is powered up is subsequently registered at the registry by associating the endpoint""s alias address with the transport address of the proxy device without replacing the alias address of an endpoint that is previously registered.
In another aspect, a Voice-over-IP (VoIP) network system is provided advantageously in accordance with the teachings of the present invention. The VoIP network system comprises a packet-switched network portion including a gatekeeper and a plurality of terminals. A cellular telecommunications network portion is coupled to the packet-switched network portion via a gateway. Preferably, the gateway operates as a proxy device on behalf of a plurality of mobile stations disposed in the cellular telecommunications network portion. The VoIP network also includes means for registering each mobile station at the gatekeeper separately and independently.
In yet another aspect, the present invention is drawn to a registration method for registering a plurality of endpoints provided in a proxy device. The proxy device is preferably disposed in a packet-switched network having a gatekeeper. The registration method starts by configuring the proxy device by setting its alias address and port address. A Registration Request message which includes the alias address of the proxy device is sent from the proxy device to the gatekeeper. A registry table in the gatekeeper is updated in response to the Registration Request message received from the proxy device. The updating step includes the step of associating the alias address of the proxy device with its transport address. Thereafter, a Registration Confirm message is sent from the gatekeeper to the proxy device.
For each endpoint that is powered up, a Registration Request message is sent from the proxy device to the gatekeeper. This Registration Request message now includes the endpoint""s alias address. In response, the registry table in the gatekeeper is updated based on each endpoint""s alias address received in the Registration Request message by associating the alias address to the transport address of the proxy device and without replacing or deleting a previously registered alias address. A Registration Confirm message is sent from the gatekeeper to the proxy device after updating the registry table in the gatekeeper in response to each endpoint""s alias address received.